A+ 2025/2026
What controls would you adjust if known targets we're not being detected on your radar?
- Gain, suppressions, range scale
Which of the following contributes to assessment of risk of collision?
- The rela ve mo on line (CPA/TCPA), aspect, the amount of error in calcula ons
A radar contact will remain sta onary on a rela ve mo on radar display only when it is?
- On the same course and speed is your vessel.
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You are under way at 10 knots. At 1800 you note a radar contact dead ahead at a range of 10
miles. At 1812 the contact is s ll dead ahead but at a range of eight miles. The es mated speed
of the contact is?
- Dead in the water (DIW)
You are underway at 5 knots in C on your radar a contact Tim miles directly astern of you. 12
minutes later the same contact is at 8 miles directly astern a few. What is the es mated speed
of the contact?
- 15 knots
The closest point of approach (CPA) of a contact on a rela ve mo on radar may be determined:
- a2er the contact has been marked at least twice over a period of at least a minute.
A radar display in which the orienta on of the display is fixed so that the north is always at the
top of the screen is called a/an?
Stabilize Display
What are the inputs to maintain a northup, true mo on display?
- gyro course and log speed
In addi on to ARPA informa on, an ARPA user should take into account:
, - The limita on is the informa on, rules of the road, the circumstances of the situa on including
external considera ons.
In restricted visibility what should you avoid when altering course for a vessel forward your
beam that you cannot see visually?
- Altering course to port except in overtaking situa ons.
when two ARPA equipped ships collide, which of the following is typically true?
- both vessels are likely to be found at fault.
When using an ARPA, what should you consider in order to evaluate the informa on displayed?
- Naviga onal constraints may require a target vessel to change course.
Which of the following informa on is least dependent on ARPA processing?
- EBL/ VRM lines
According to IMO, log in speed indicators providing inputs to ARPA equipment should be
capable of providing:
- the ship speed through the water
what is the minimum number of targets that an IMO approved ARPA must track
simultaneously?
20
What is the lowest range scale that IMO requires ARPA facili es to be available on?
3 miles
According to IMO standards, the ARPA data display:
regarding the IMO requirements for past posi ons:
- all ARPA's can display both true and rela ve past posi ons
IMO requires ARPA to operate in rela ve mo on with:
- North up, and course up displays.
According to IMO performance standards, what should an ARPA do to improve the standard of
collision avoidance at sea? [IMO Performance standards for ARPA 1.1.1]
- ARPA Should reduce the workload of observers by automa cally providing informa on.